Here you can find the source of instanceOf(Object obj, String className)
public static boolean instanceOf(Object obj, String className) throws ClassNotFoundException
//package com.java2s; /**//from w ww.j a va 2 s .c om * Licensed to Apereo under one or more contributor license * agreements. See the NOTICE file distributed with this work * for additional information regarding copyright ownership. * Apereo licenses this file to you under the Apache License, * Version 2.0 (the "License"); you may not use this file * except in compliance with the License. You may obtain a * copy of the License at the following location: * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ public class Main { public static boolean instanceOf(Object obj, String className) throws ClassNotFoundException { final ClassLoader cl = obj.getClass().getClassLoader(); final Class<?> clazz = Class.forName(className, true, cl); final boolean isInstanceOf = obj.getClass().isAssignableFrom(clazz); return isInstanceOf; } }